Programming Erlang, 2nd Edition

Variables

We can store the result of a command in a variable.

In the first line we gave a value to the variable X; in the next line the shell prints the value of the variable.

Note that all variable names must start with an uppercase letter.

Single Assignment Is Like Algebra

When I went to school, my math teacher said, “If there’s an X in several different parts in the same equation, then all the Xs mean the same thing.” That’s how we can solve equations: if we know that X+Y=10 and X-Y=2, then X will be 6 and Y will be 4 in both equations.

But when I learned my first programming language, we were shown stuff like this:

Everyone protested, saying “You can’t do that!” But the teacher said we were ...